Self-regulation is pivotal for human well-being and mental health. In this qualitative study, we followed a randomized controlled trial (RCT) and explored how a five-day residential mindfulness program in a restorative natural setting supported self-regulation among university students experiencing moderate to severe stress. Six participants were interviewed post intervention and at three months’ follow-up on how they experienced the retreat. Through interpretative phenomenological analysis, four interrelated themes emerged: “supportive conditions”, “attitudes of mindfulness”, “connection” and “physical and psychological balance.” These themes reflected the outcomes of the retreat that participants valued in stressful situations. A progression occurred during the retreat through the themes, with emphasis developing from the supportive conditions of the setting, to cultivating mindful attitudes, over connection to both self, others and nature, to changes and effects on the physical, psychological and even spiritual level. In addition, participants emphasized experiences of positive emotions, energy, calmness, meta-awareness and the feeling of being part of the web of life. In conclusion, participants’ experiences with a five-day nature-based mindfulness intervention revealed a range of qualities of both physical-, psychological-, social- and spiritual nature that are supportive for self-regulation.